AddBackPredPB

Performs bidirectional prediction for a B-block in a PB-frame.

Syntax

IppStatus ippiAddBackPredPB_H263_8u_C1R(const Ipp8u* pSrc, int srcStep, IppiSize srcRoiSize, Ipp8u* pSrcDst, int srcDstStep, int acc);

Parameters

pSrc	Pointer to the origin of the source image (P-macroblock) region of interest (ROI).
srcStep	Width in bytes of the source image plane, that is, distance in bytes between the starting ends of consecutive lines of the source image.
srcRoiSize	Size of the source ROI.
pSrcDst	Pointer to the origin of the source-destination image ROI, that is, bidirectionally-predicted part of the block.
srcDstStep	Width in bytes of the source-destination image plane.
acc	Parameter that defines pixel accuracy for backward prediction: bit 0 (the least significant bit) contains the half-pixel offset in horizontal direction, bit 1 - the offset in vertical direction.

Description

The function ippiAddBackPredPB_H263_8u_C1R is declared in the ippvc.h header file. This function calculates backward prediction for a B-block of a PB-frame and adds it to the block, previously reconstructed with forward prediction. All the operations are restricted to the bidirectionally-predicted part of the B-block. The parameter srcRoiSize defines the area size. The backward prediction is performed with pixel accuracy defined by acc, and the sum of the forward and backward predictions for every pixel within srcRoiSize is divided by 2 (division by truncation). The bidirectional prediction procedure is specified in [ITUH263], Annex G, clause G.5, bidirectionally- and forward-predicted areas for a B-block are demonstrated in [ITUH263], Annex G, Figure G.2.

This function is used in the H.263 decoder included into Intel IPP Samples. See introduction to H.263.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error condition if at least one of the specified pointers is NULL.
ippStsSizeErr	Indicates an error condition if srcRoiSize has a field with zero or negative value.